Apparatus for improving the operation of oxygen cutting torches



We 14, 1949. p, BETZ APPARATUS FOR IMPROVINGTHE OPERATION OF OXYGEN CUTTING TORCHES Filed Dec. 5, 1945 dug IIQ'VHVTOR. OK Wm/Maflwm attorn ys Patented June 14, 1949 UNITED. srrss APPARATUS FOR IMPROVING THE OPERA- TION OF'OXYGEN CUTTING TOBCH E s Paul L. Betz, Baltimore, Md., assignor to Con- -rsolidated Gas Electric Light and Powerv Com-s pany of Baltimore, Baltimore, Md., -ajcorporation of Maryland J L QFFJ-CE 3, E li-Serial No. 632,576

This invention relates to oxygen cutting torches, and more particularly to means for improving the operation ofsuchftorches. I'his application is adivision of my application Serial No. 445,951, filed June 5, i 1942, Patent N0.

which includes-therein a valve for controlling the flow-of cutting oxygen. The mixing chamber supplies a mixture of oxygen: and fuel gas to the preheat portsofthe torch tip,- and the cutting oxygen is directed to 'aseparate port in said tip.

During the preheatingof the work, the rate of how of oxygen is smalland the oxygen pressure of the torch isclose to that whichis obtained at the output side of the pressure regulator, since with such a small flow. of oxygen the pressure drop in the oxygen supply hose is negligible. When the ignition point of themetal is reached and the cutting oxygen valve is opened, however, the quantityof oxygen flowing through thehose be increased'as much-as sixor eightfold, and

this highrate-cfoxygeir'flow causes a considerable pressure drop-intheoxygenhose: Also, it is usually found that under normal operating conditions, the oxygen pressure regulator is unable tomaintain the original *oxygen. pressureat its "15 Claims. (01. 158--27.4)

outlet side when cutting oxygen is flowing because of the -magnitudeof .thepressure drop. Hence thereare'two factors which lower 'the'oxygenpressure at thetorch" during cutting. 'Theeffect of said lower oxygen-pressure at the torch a 1946 during cutting is tocausea reduced amount of 352% o: the cutting or burning preheat oxygen to be supplied-tothe torch-while of metals, oxygen and a fuel gas are supplied to the "cutt ng 'i progress; andswhile with some a torchwhere mixing occurs in such proportions fuels this reduction in preheat o y lfl durmg asto give a satisfactory'preheat flame. This 10 ting maybe of l ttle conseq n r h other flame, when applied tothe meta-Ito be cut, causes s t u tmn 1n pr atvoxye n auses the the temperature to rise. locally until the ignition flame e p ature 30 decrease to Such'an exor kindling temperature is reached, and at that tenli'Whl1eihe0uttmg f d W yat under time a valve isopened-to supplya jet of oxygen some colldlljlons t D QQSS y e'se lwhich strikes the heated metal and causes the lf handlqapped le je yfl, metal to burn freely in the oxygen atmosphere. It 1s an ob ect of this invention to provide novel The usual equipment used. for metal cutting means sct fl w--= y en to oxyby this process includes a supply of high pressure l i rche W111 h -W11-1 overcome the for oxygen which passes through, a pressure regu goingdifiicul-tiesand-avoid the pressure drop in later to a length of flexible hose to which is con- 20 the Pr Oxygen n t e utting oxygen nected the cutting torch. A-source of fuel gas Valve 15 Opened; 71 under high pressure is 1 connected to the A further obJect of this invention is to provide torch by alength of flexible hose, and within the mealjls 'thflltype K I F d 0h an be torch, a throttle valve is usually provided to perreadlly l exlstlgng-lv t s can mit adjustment Ofthe flow of fuelgasltothe 25 be readily incorporated in new-installations and h b ofaghe torch Two paths areusually which assures thatasubstantiallyconstant oxyprovided in the torch for the oxygen, one of which gen presfiure 1S ma1nta1neqat the torch Whet er includes therein a -throttle valve to control the cuttmg mfygen ValYe P flow gf Oxygen to mixing chamber of the Another oblectof this invention is toprovide torch for preheat fl m anduthe nthel. of 3) an oxygen cutting torch with relatively simple means for carrying out. the aforesaid objects:-

Another object ofthisinventionis to provide an oxygen cutting torch witlrmeans whereby there is no substantial reductioninpreheat oxygen pressure during the cutting process over what exists duringpreheating. g i

Another objectzof this invention is to provide an oxygen cutting-torch with means'which assures that a substantially constanthoxygen supply pressure is maintained both duringpreheating and during progress of the cutting.

Another object of this invention is to provide a device of the type characterized which is simple and compact instructurei. g s

Another object of this invention is to provide a device of the type characterized which maybe readily incorporated inexisting installations of cutting torches as'well as in'new torches.

Another object ofthis invention 'is to provide device of the type "characterized whichreadily lends itself to remote 'controlas well as to control 'of an operating lever E l.

by the usual valve operating means located at the torch.

Another object of this invention is to provide a device of the type characterized which may be readily embodied in cutting torches in association with the usual valve means at the torch without materially adding to the weight or bulk of the structure.

Another object of this invention is to provide a device of the type characterized which is easy to manipulate and efficient and certain in operation.

Other objects of the invention will appear as the description thereof proceeds.

The invention is capable of being carried out in a variety of ways and receiving a Variety of mechanical expressions, some of which are illustrated on the accompanying drawings, but it is to be expressly understood that the drawings are for purposes of illustration only, and are not to be construed as a definition of the limits of the invention, reference being had to the appended claims for that purpose.

Referring in detail to the drawings, wherein the same reference characters are used to indicate corresponding parts in the several figures,

Fig. l is a diagrammatic view illustrating the present invention embodied in a more or less conventional oxygen cutting torch installation,-

Fig. 2 is an axial section of a structure embodying the present invention;

Fig. 3 is a top plan view of the device of Fig. 2; and

Fig. 4 is a top plan view of another embodiment of the present invention.

Referring first to Fig. 1, which shows diagrammatically an oxygen cutting torch installation, a source of high pressure oxygen is indicated at H], and in the outlet therefrom is disposed a pressure regulator I l with which communicates tubing l2 for conveying gas to the mixing chamber it of a cutting torch M. A source of fuel gas is indicated at 15, and in the outlet therefrom is disposed a pressure regulator 16 with which communicates tubing I1 for conveying fuel gas to the mixing chamber is of the torch. A throttle valve is indicated at E8 in the gas passage l9 communicating with the tubing ll and the mixing chamber IS. The oxygen flowing through tubing 12 has two paths respectively designated 2G and 2!, the former being the path for preheat oxygen and the latter being the path for cutting oxygen. A throttle valve 22 is indicated in the passage for the preheat oxygen, and a valve 23 is indicated in the passage 2! for the cutting oxygen. Cutting valve 23 is ordinarily of the quick-acting type so that full flow of oxygen may be established by manual operation thereof, as by the depression The valves l8, 22 and 23 and the lever 2d are usually assembled into a unit as diagrammatically indicated by the block 25 containing the aforesaid passages with the valves therein and operating means therefor supported thereon. The structure as so far described is already known commercially and forms no part of the present invention.

In conformity with the present invention, means are associated with the cutting torch as so far described to overcome the difficulty heretofore explained due to the drop of pressure of the cutting oxygen and to maintain a substan- 4 tially constant oxygen pressure both during preheating and during the progress of the cutting. A device so embodying the present invention may be applied as an auxiliary device to existing torches, or it may be built into new torches as a component part thereof. When applied to a torch, there are two types of installation to be considered, i. e., torches for automatic or machine cutting and torches for manual cutting. In the case of automatic cutting the device of the present invention may be mounted on or incorporated in the cutting machine proper. In the case of manual cutting, however, it may be desirable to avoid placement of the device on the torch itself because of the additional weight involved, and in this case the auxiliary device may be installed in the oxygen supply line close to the torch but sufficiently removed therefrom to permit the torch to be handled in the usual way.

A device embodying the present invention is indicated schematically at 30 in Fig. 1 and contains th by-pass valve to be referred to. As here shown, a throttle valve 3|, manually adjustable for a purpose to be explained, is interposed between the oxygen tube connection 32 with tubing is and the supply connection 33 with the passages 26 and 23 leading to the torch. Throttle valve 3! is icy-passed by means of a passage 34 in which is placed a valve 35, preferably of the quick acting type so that it may be fully moved between closed and open positions by a simple manipulation. A ire is employed to indicate the in pressure in the connection 33 leading to the torch. The by-pass valve 35 is operatively connected in any suitable way with the means for op rating the valve 23, so that by-pass valve 35 is operated whenever valve 23 is operated. Thus, when valve 23 is opened, by-pass valve 35 is opened, and when valve 23 is closed, by-pass valve 35 is closed. By-pass valve 35 may be linked mechanically to the valve 23, so that they are operated together by the operating lever 2d as explained in connection with the embodiments of Figs. 2 to 4, or by-pass valve 35 may be a solenoid type valve energized by a circuit which includes a suitable switch 38 associated with the valve 23 and circuit connections 37 so that when the lever 24 is depressed to open valve 23 the switch may be closed to energize the solenoid and open valve 35.

Fig. 1 illustrates a case wherein the present invention is incorporated in a device directly connected to the cutting torch. Where manual cutting is to be done, it may be desirable to separate device 34} from the cutting torch by a short length of tubing so that the torch may be handled in the usual manner. In this case, the tubing is to be interposed between the connection 33 and the outlet side of the device 30, and valve 35 in that case would preferably be of the solenoid type because of the ease of operating such a valve by a circuit making and breaking device associated with the operating lever 24.

To illustrate th use of the present invention, assume that by opening valves 3! and 35 the torch may be used in the usualmanner but the pressures existing at the torch as so used may be determined by reference to the pressure gauge 36. Thus the drop in oxygen pressure between preheat and cutting conditions may be determined. For example, suppose the pressure on the outlet side of the oxygen regulator l l is adjusted to fifty pounds per square inch for a desired flow of preheat oxygen. With the relatively low flow of preheat oxygen the pressure at the gauge 36, indicating the pressure at the torch, would be approximately fifty pounds per square inch during the preheat operation, since the frictional drop of pressure through the tubing would be small.

Upon opening the; cutting oxygen valve 2'3, however, the increased flow of oxygen will cause the pressure at the outlet of the regulator II to drop--say five pounds, i. e., to forty-five pounds per square inch due to, the more rapid flow of per square inch between preheat andcutting conditions. This variation, may be eliminated by using the present invention in the following manner. Let us assume that the desired constant oxygen pressure for preheating and cutting is fifty pounds per square. inch. First, regulator l l is adjusted to maintain the oxygen pressure at the torch at fifty pounds per square inch and preheat oxygen valve 22 and fuel valve l8 are adjusted to give the desired preheating mixture. During this operation, valves 23 and 35 remain closed, valve M is open and oxygen pressure is determined on gauge 36. Next, valves 25 and 35 are opened, thereby initiating the flow of cutting oxygen and regulator H is readjusted to restore the oxygen pressure at the torch to fifty pounds per square inch, as indicated on pressure gauge 3t. Following this cutting oxygen valve 23 is closed together with, the by-pass valve 35 to establish preheat conditions. It will now be observed that the pressure indicated on the gauge 36 rises above fifty pounds per square inch due to the adjustment that has been. made at the oxygen regulator ll. Thottle valve M is now adjusted until the pressure gauge 36 again indicates an oxygen pressure of fifty pounds per square inch under conditions of preheat, this being the pressure at which the preheat adjustment was originally made. Therefore, the quantity of preheat gen is now the same as before since the oxygen pressure is the same. When by-pass valve 35' is opened simultaneously with the oxygen cutting valve however, the increased flow of oxygen provided by the by-pass. 34' will, under the conditions assumed, assure that the oxygen pressure at the torch, as indicated by the gauge 36,

is again fifty pounds per square inch for the cutting operation. Thus by somewhat increasing the oxygen pressure at the outlet of the source Ill to assure the desired pressure at the torch when the by-pass S ll is opened and throttling the Howl-155 of pre-heat oxygen by valve 3 I, the same pressure may be maintained at the torch both during preheating and while cutting is in progress.

As an alternate, though more approximate, method, the adjustment may be made as follows. With valve 22 closed or partially closed the cutting oxygen valve 23 is opened together with by-pass valve 335 and the oxygen regulator H is adjusted to provide the desired cutting oxygen pressure at th torch, as indicated on gauge 36. oxygen valve 23 is then closed together with bypass valve 35, and the desired preheat adjustment is made using fuel valve it and oxygen valves 3! and 22-, care being taken that the adjustment of throttle valve 3| is such as to provide the above referred to cutting oxygen pressure at the torch, when the desired preheat adjustment is attained. By this adjustment, the change in oxygen pressure at the torch between cutting and preheat conditions may be reduced or eliminated according to Cutting the closeness with which the preheat oxygen flow during the adjustment of regulator H approaches the required preheat oxygen flow for the preheat adjustment, involving manipulation of valves l8, 3! and 22, as outlined above.

As so far described, the invention has been treated as embodied in a form whereby it may be interposed in th oxygen connection to the torch. The present invention, howevenmay be readily embodied in the torch structure itself without materially increasingthe weight or bulk thereof. Figs. 2 to 4 illustrate embodiments whereby the by-pass 34 and associated valves 3!, 35 may be readily combined in the unit which has heretofore included the valves l8, 2?. and 23, together with their actuating means. For simplicity, the passage for the fuel gas and; its throttling valve have been omitted from the section and plan Views of 2 to 4, but it is to be understood that the structure to be described would be provided with a passage, such as is in Fig. 1, and a throttle valve, such as is in Fig. 1, for controlling the how. of fuel gas as hereinbefore described.

Focusing attention on the oxygen passages and valves, any suitable base structure ll] is. provided with an inlet passage 4 l here shown as having an exteriorly threaded nipple d2, corresponding to the connection 32 of Fig. 1. Base 49 is provided with an interior chamber 43 closed by a removable end plug as, and said chamber may communicate with the passage All through a port 45 provided with a valve seat 46. Cooperating with valve seat it is a valve member t? which is normally urged into closed position by a coil spring is reacting between said valve member and a spring seat is on the plug Ml. Valve member ll be opened against the tension of its spring by slidable pin extending through an aperture 5| in the wall of the passage ll and having a suitably packed gland 52 to prevent leakage of oxygen. At its outer end said pin 58 cooperates with a manually operated device of any suitable construction, here shown as in, the form of a lever 53 pivotally mounted at Ed on lugs 55 projecting from the base ill]. As will hereinafter appear, valve 46, ill corresponds in function and operation to the lay-pass valve 35 of Fig. 1.

Also formed in the base it is a passage 5t which communicates with the passage ll and the chamber 33, and interposed in this passage is a throttle valve El of any suitable construction provided with a manually operable hand wheel 58. Throttle valve 5'? corresponds in function to the throttle valve sf of Fig. l, and when the valve 36, Ill is closed the preheat oxygen flows through the passages ill and 56 to the chamber 43 in volume as determined by the throttle valve 51.

Also formed in the base id is a passage 59 which communicates with the chamber 53 through Also communicating with passage iii leading to any suitable connection which, is the preheat oxygen connection corresponding to the connection 2%) of 1. Associated with said passage El is a throttle valve 63 of any suitable construction, here shown as of the same form illustrated at 5'1, said valve having an operating hand wheel fi l. fral'we,v is a throttle valve for the preheat oxygen and corresponds in function to the valve 22 of Fig. l.

Communicating with the passage 59 through a port 65 having a valve seat. Ed is a chamber 5'! in which is disposed a valve member 68. Chamber 61' is closed by removable end plug 69, and the valve 68 is normally urged toward closed position by a cOil spring 1|] reacting between valve member 68 and a suitable spring seat H on the plug 69. It will be observed that chamber ti with its contained valve mechanism may be of the same size and construction as the chamber 43 with its contained valve mechanism. Communicating with the chamber 6? is an outlet passage 72 to which is connected the connection for the cutting oxygen. Valve member tii cooperates with a pin 13 slidably extending through an aperture 14 in the wall of the passage 59 and having any suitable gland 15 to prevent leakage of oxygen. Pin '13 at its outer end cooperates with the lever 53 heretofore referred to. Valve 63, 68 corresponds in function to the valve 23 of Fig. 1 and the outlet passage 12 corresponds to the passage 2| of Fig. 1.

Also communicatin with the passage 59 is a passage '56 leading to any suitable connection Tl extending to a pressure indicator such as diagrammatically indicated at 36 in Fig. 1.

When lever 53 is depressed both of the pins 50 and 13 are moved inwardly to move valve members 4? and 68 off of their respective seats 46 and 66, and cutting oxygen may flow from the passage 4i through port 65 to chamber and through passages til, 59, port 55 and charm her 6'? to outlet connection 12. Thus the valves as shown in Fig. 2 function in the way as the valves above described in conjunction with the embodiment of Fig. 1. It will also be observed that analogously as the connection to the pressure indicator 36 in Fig. 1 is on the torch side of the valves 3| and 35, and ahead of the valves 22 and 23, so in Fig. 2 the connection to the pressure indicator at '16 is on the torch side of the valves 46, ll and and ahead of the valves 53 and 66, 68. Accordingly, the embodiment of Fig. 2 may be operated and set for maintaining the fixed and predetermined pressure of oxygen flow both during preheat and the progress of the cutting operation as above described in conjunction with the embodiment of Fi 1.

In the embodiment of Figs. 2 and 3 the lever 53 which operates the pins 50 and 13 has different lever arms so that the magnitude of movement of the valve members 47 and 58 will be different. In some cases it may be desirable to provide equal magnitudes of movement for the valve members ll and 68, and Fig. 4 illustrates an embodiment of the present invention in which this result is accomplished. The structure of the base member 40 and its contained or supported passages, valve means, etc., are or may be the same in Fig. 4 as in Figs. 2 and 3, and the same reference characters have been used to indicate corresponding parts. In Fig. 4, however, the operating lever 80 is pivoted at 8| transversely to the length of the base MI and the pins l3 and 5B operated by said lever 88 are at equal distances from the axis of the lever Bil so that the magnitude of movement of the valve members 68 and M is the same.

It will therefore be perceived that by the present invention an oxygen cutting torch has been provided with means whereby opening of the valve controlling flow of cutting oxygen does not cause a diminution in pressure of the oxygen flowing to the port for preheat oxygen, and therefore the difiiculties heretofore encountered by reason of such drop in the preheat oxygen, in devices as heretofore constructed, have been entirely overcome. Furthermore, the device accomplishing the aforesaid results is one that canbe readily applied to installations of oxygen cutting torches already in use, whether for machine cutting or for manual cutting, and the invention may also be equally embodied in new torches as well as applied as an auxiliary device for existing installations. In either event, the present invention provides a relatively simple, compact and easily manipulated device which accomplishes the foregoing results with certainty and efiiciency and as the manipulations required for obtaining the novel results are relatively simple in character they may be readily and satisfactorily performed by the usual operators of devices of this character.

While the embodiments of the invention illustrated on the drawings have been described with considerable particularity, it is to be expressly understood that the invention is not restricted thereto. As will now be apparent to those skilled in the art, this invention may be carried out in a variety of ways and with structures of a wide variety of form. While the invention has been exemplified by preferred structures, the invention in its broader aspects may be incorporated in a wide variety of devices, and changes may be made in the details of construction and arrangement of the passages, valve means, op" erating means for the valve means, etc., without departing from the spirit of this invention. Reference is therefore to be had to the appended claims for a definition of this invention.

What is claimed is:

1. In a device for controlling the flow of oxygen to an oxygen cutting torch having separate passages for flow of preheat oxygen and cutting oxygen and a fuel passage and a valve at the torch for controlling flow of cutting oxygen, the combination of means providing two oxygen passages in parallel having outlets in communication with said first named oxygen passages, one of said passages including a non-throttling valve for openin and closing said passage and the other of said passages including a throttling valve disposed in said passage on its upstream side from its outlet, and means for operating said non-throttling valve simultaneously with the operation of said valve on the torch for controlling the flow of cutting oxygen.

2. In a device for controlling the flow of oxygen to an oxygen cutting torch having separate passages for flow of preheat oxygen and cutting oxygen and a fuel passage and a valve at the torch for controlling flow of cutting oxygen, the combination of means providing two oxygen passages connected in parallel and having a common outlet in communication with said first named oxygen passages, one of said passages including a non-throttling valve for opening and closing said passage and the other of said passages including a throttling valve on the upstream side from said outlet, means for operating said nonthrottling valve simultaneously with the operation of said valve on the torch for controlling the flow of cutting oxygen, and pressure indicating means associated with the outlet of said parallel connected passages for determining the pressure of the oxygen when said non-throttling valve is open and closed.

3. In a device for controlling the fiow of oxygen to an oxygen torch having separate passages for fiow of preheat oxygen and cutting oxygen and a fuel passage and a valve at the torch for controlling flow of cutting oxygen, the combination of means remote from said torch and providing 76 two passages in parallel, means providing communication between said last named passages and said first namedoxygen passages one of said passages including a non-throttling valve for 'opening and closing said passage and the other of said passages including a throttling valve on its upstream side from said communicating means, and electromagnetic means operatively "connectedto said non-throttlingvalve and actuated by 'said valve on the torch for controlling fiow of cutting oxygen for opening and closing 'said non-throttling and cutting oxygenvalves in outlets in communication with said first named oxygen passages, none of said passages including a non-throttling valve for opening and closing said passage and the other of said passages including a throttling valve on the upstream side from its outlet, and mechanical means interconnecting said non-throttling valve and said valve at the torch for controlling flow of cutting oxygen for opening and closing said non-throttling and cutting oxygen valves in unison.

5. In a device for controlling the flow of oxygen to an oxygen cutting torch having separate passages for flow .of preheat oxygen and cutting oxygen and a fuel passage and a valve at the 'torchfor controlling flow of cutting oxygen, the

combination of means providing two passages in parallel having a common outlet in communication with said first named oxygen passages, one of said passages including a non-throttling valve for opening and closing-said passage and the other of said passages including a throttling valve on the upstream side of said outlet, and common means operatively connected to said non-throttling valve and said valve at the torch for simultaneously opening and closing said non-throttling and cutting oxygen valve to control the flow of cutting oxygen.

6. In a device for controlling the oxygen pressure at an oxygen cutting torch having means providing a fuel passage and separate passages for the flow of preheat oxygen and cutting oxygen and valves for said passages including a valve for opening and closing the passage for cutting oxygen and means for operating said cutting oxygen valve, the combination of means providing a pair of passages in parallel with each other for respectively conveying preheat oxygen and cutting oxygen, said passages having a common inlet and a common outlet in communication with said first named oxygen passages, a throttling valve in that one of said last named passages which conveys preheat oxygen and on the upstream side of said outlet, a non-throttling valve for opening and closing the other of said last named passages, and means for operating said last named valve from said operating means for the cutting oxygen valve.

'7. In a device for controlling the oxygen pressure at an oxygen cutting torch having means providing a fuel passage and separate passages for the flow of preheat oxygen and cutting oxygen and valves for said passages including a valve for opening and closing the passage for cutting oxygen and means for operating said cutting oxygen valve, the combination of means providing a pair of passages in parallel with each other for respectively conveying preheat oxygen and "cutting oxygen, said passages having -a common inlet and a common outlet -in communication with saidfirst'named oxygen passages, a throttling valve in that one ofsaid last named passages which conveys preheatoxygen and on" the upstream side of said outlet, a non-throttling valve'for'openingand closing the other'of said last named passages, means for operating said last named valve from-saidoperating means for the cutting oxygen valve and pressure indicating means in communication with said last named passages-and responsive tothe oxygen pressure therein on the outletsides'of the valves in said passages.

'8. In a device for controlling the oxygen pressure'of an oxygen cutting torch having means 'providinga fuel passage and separate passages for the flow of preheat oxygen and cutting oxygen and valves for said passages including a-valve for opening and closing the passage'for cutting oxygen and means for operating said cutting oxygen valve, the combination of means providing a pair of passages in parallel-with each other for respectively conveying preheat oxygen and "cutting oxygen, said'passages having a common inlet and a common outlet in communication with-saidfirstnamed oxygen passages, a throttling valve in that one of said last named passages which conveys preheat oxygen and on the'upstreamside of said outlet, a non-throttling valve for 'opening and closingthe other-of said last named passages, and means for operating said last named valve operated by said operating means for the cutting oxygen valve, said operating means'including a lever pivotedon said passage-providing means and members operated by said lever-for"simultaneously opening or closing said non-throttling valve and said valvein said cutting oxygen passage.

9. In a device for controlling the flow of oxygen to an oxygen cutting torch, a base member provided with a chamber, means having an outlet for cuttinngoxygen communicating with said chamber, means providing a passage for the flow of preheat oxygen around said chamber but having a port communicating with said chamber, means providing a second chamber communicating with said passage, means forming an inlet passage and having a port communicating with said second chamber, valves controlling said ports, a common operating means for said valves, means providing a passage around the valve in said second chamber, and a throttling valve in said last named passage.

10. In a device for controlling the flow of oxygen to an oxygen cutting torch, a base member provided with a chamber, means having an outlet for cutting oxygen communicating with said chamber, means providing a passage for the flow of preheat oxygen around said chamber but having a port communicating with said chamber, means forming a second chamber communicating with said passage, means providing an inlet passage having a port communicating with said second chamber, valves controlling said ports, a common operating means for said valves, means providing a passage around the valve in said second chamber, a throttling valve in said last named passage, and means communicting with the passage around said first named chamber for indicating the pressure.

11. In an apparatus for controlling the flow of oxygen to an oxygen cutting torch, a base memalways open for the flow of preheat oxygen, an adjustable throttling valve in said passages, means providing a passage in communication with said first named passages at opposite sides of said throttling valve for the flow of cutting oxygen around said throttling valve, a valve for controlling said last named passage, means providing a passage communicating with said first named passages for the flow of cutting oxygen, a valve controlling said last named passage, and common actuating means for controlling both of said last named valves.

12. In an apparatus for controlling the flow of oxygen to an oxygen cutting torch, a base member providing communicating passages which are always open for the flow of preheat oxygen, an adjustable throttling valve in said passages, means providing a passage in communication with said first named passages at opposite sides of said throttling valve for the flow of cutting oxygen around said throttling valve, a valve for controlling said last named passage, means providing a passage communicating with said first named passages for the flow of cutting oxygen, a valve controlling said last named passage, common actuating means for controlling both of said last named valves, and pressure indicating means communicating with said first named passages between said two last named valves.

13. In an apparatus for controllin the flow of oxygen to an oxygen cutting torch, a base member providing communicating passages which are always open for the flow of preheat oxygen, a pair of adjustable throttling valves in said passages, means providing a passage in communication with said first named passages at opposite sides of one of said throttling valves for the flow of cutting oxygen around said last named throttling valves, a valve for controlling said last named passage,

means providing a passage communicating with 40 said first named passages for the flow of cutting oxygen, a valve controlling said last named passage, and common actuating means for controlling both of said last named valves.

14. In a device for controlling the flow of oxygen to an oxygen cutting torch, a base member providing communicating passages for the flow of cutting oxygen, said passages having therein two valves arranged in series, means providing a passage in parallel with the passage controlled by one of said valves and in communication therewith at opposite sides of said last named valve, a throttling valve for controlling said last named passage, means providing a passage for oxygen around the other of said first named valves, a throttling valve for controlling said last named. passage, and common actuating means for said two first named valves.

15. In a device for controlling the fiow of oxygen to an oxygen cutting torch, a base member providing communicating passages for the flow of cuttin oxygen, said passages having therein two valves arranged in series, means providing a passage in parallel with the passage controlled by one of said valves and in communication therewith at opposite sides of said last named valve, a throttling valve for controlling said last named passage, means providing a passage for oxygen around the other of said first named valves, a throttling valve for controlling said last named passage, a common actuating means for said two first named valves, and means in communication with the passages between the said first named valves for indicating the oxygen pressure thereat.

PAUL L. BETZ.

REFERENCES CITED The following references are of record in the 

